ALBANY — New York auditors reported uncovering 325,000 errors and inconsistencies in prescriptions for painkillers and other commonly abused drugs in a review of 28.5 million prescriptions dispensed over 15 months.

The audit said the state Health Department's Bureau of Narcotic Enforcement has tightened processes but it still faulted poor controls over unused prescription forms and inconsistent bureau inspection practices. Comptroller Thomas DiNapoli said the bureau needs to pursue new ways to prevent, detect and prosecute prescription fraud, while acknowledging a new law to curb abuse by requiring electronic prescriptions and a statewide database for "real time" online review.

The painkillers Oxycodone and Hydrocodone and the sleep drug Ambien accounted for nearly half the drugs auditors found filled 565,000 times in 2010-2011 from prescriptions with errors or inconsistencies. "The abuse of prescription medications has reached epidemic proportions and the costs to society are enormous," DiNapoli said.

The audit showed 130,000 prescriptions with an invalid Drug Enforcement Administration number not matching the prescriber. Another 180,000 prescription numbers appeared twice, indicating they were filled at multiple locations or with inconsistent information, while 90,000 were refiled more than 157,000 times beyond their authorized refill quantities.

In their response to the audit, state health officials said the changes under the law signed in August will help eliminate paper prescriptions and illegal diversions, while enabling the bureau to share more information with doctors, pharmacists and police.

Electronic prescribing is scheduled to be mandatory in New York starting Dec. 31, 2014, according to the Health Department.

Meanwhile, the bureau is updating its computer system and expanding its analytical staff and said it is "well aware" of the value of data mining.